Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 5)
5.
A train passes a station platform in 36 seconds and a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, what is the length of the platform?
120 m
240 m
300 m
None of these
Answer: Option
Explanation:

Speed = 54 x 5 m/sec = 15 m/sec.
18

Length of the train = (15 x 20)m = 300 m.

Let the length of the platform be x metres.

Then, x + 300 = 15
36

x + 300 = 540

x = 240 m.

Discussion:
276 comments Page 14 of 28.

Paridhi said:   1 decade ago
Should we not consider the length of man? Why do we take it as a reference point?

Rasik said:   1 decade ago
Guys the total time to cross the platform is 36 sec with speed of 15 m/sec i.e. d=s*t.

36*15=540 m. Hence option is none of these.

Shubham Gupta said:   1 decade ago
s = d/ t.

Length of train = s*t = 15 m/sec*20 sec = 300 m.

Now let length of platform = x m.

Total length = (300+x) m.

s = d/t.

15 = 300+x/36.

x = 240 m answer.

Praveen said:   1 decade ago
s = d/ t.

Length of train = s*t = 15 m/sec*20 sec = 300 m.

Now let length of platform = x m.

Total length = (300+x) m.

s = d/t.

15 = 300+x/36.

As 123 answer = 250 m

Sangam said:   1 decade ago
Hi guy's.

Length of the train w.r.t reference point = (54*5/18)*20 = 300 m.

Consider platform platform x meter.

Distance = Speed*Time.

(X+300) = (15*36) = 540.

X = 540-300 = 240 m.

Therefore length of platform is 240 m.

Swamy said:   10 years ago
Well,

36 sec - 20 sec = 16 sec.

Then,

36 sec ----- 540 mt.

16 sec ----240 mt (train length).

Rock said:   10 years ago
Train speed = 15 m/s.

Time different = 36-20 = 16 sec.

Length of platform is 16*15 = 240 meter.

Kumarchandana said:   10 years ago
It is one of the similar way of improving our aptitude knowledge.

Kiran said:   10 years ago
Speed of the train will be null.

Suraj said:   10 years ago
First convert km/h into m/sec:

= 54*5/18 = 15.

= 15*36-15*20 = 240.


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